Safety apparatus



June'Z, 1931. F. N. WHITESELL SAFETY APPARATUS Filed Aug. 30. 1928 a lllllll o lllllllllllll ylll INVENTQR fkfozp a/r 11/7535;

ATTORNEY Patented June 2, 1931 imirs n STATES PATENT orrics FREDERICK 1v. WHITESELL, or CHICAGO, ILLINOIS, ASSIGNOR T0 FAIRBANKS, MORSE a 00., or CHICAGO, ILLINOIS, A coRroRArIoN or ILLINOIS SAFETY APPARATUS Original applications filed November 6, 1926, Serial No. 146,720, and. February 10, 1928, Serial No.

253,412. Divided and this application filed August 30, 1928. Serial No. 302,979.

This invention relates to improvements in safety apparatus, and particularly to a safety device adapted to be used with a fluid-pressure controlled hoisting mechanism.

3 The specific example described constitutes a safety control means for an automatic drum hoist, but it will be understood that the improvements, hereinafter described, are equally adapted for use with other control mechanism.

In hydraulic controlled mechanisms, the fluid-pressure in the system, may at times, for certain causes, fall below a predetermined operating pressure. In such case, the mechanism being operated from a source of power other than the hydraulic system, will continue to operate, and thereby causean interference in the sequence or cycle of operation of the control means. Further, any substantial irregularity in the pressure may actuate the control means out of sequence with the operating mechanism in a manner to cause injury to men and equipment. This disadvantage has been obviated by the use of an improved safety device, hereinafter described, which is adapted for use with a hydraulic control system, as a source of pressure supply, but which operates responsively to irregularities of pressure, to set the controls of the hoist or like equipment.

One of the objects of the present invention is to provide an improved safety apparatus for use with a hydraulically controlled mechanism, such as a hoist or thelike, paratus provides maximum safety in operation, and which has means associated therewith for automatically stopping the mechanism, in the event the regular cycle ofoperation is interrupted, or interfered with for any cause.

A further object of my invention is to provide means whereby the operating mechanism is automatically stopped whenever the fluidpressure in the hydraulic system is, for any cause, lowered beyond a predetermined value.

A still further object is to provide an improved safety device which will not interfere with the usual operating cycle of the control .mechanism of hydraulically controlled conveying apparatus.

,tary view appearing in Fig. 2, but showing the lever which ap- An additional object is to provide an improved safety apparatus with means for locking the control shaft of a drum hoist, in a neutral position, and a fluid-pressure responsive means for placing the control shaft in operating position.

A still further object is to provide an improved construction in safety apparatus of the type mentioned, to permit its adjustment to varying working conditions.

Further objects and advantages of this invention will appear from the following detailed description of parts and the accompanying drawings thereof, and from my copending applications, Serial No. 146,720, filed November 6,1926 and Serial No. 253,412, filed February 10, 1928, of which the present subject matter is a division. 4

In the drawings, Fig. 1 is a plan view of a preferred form of the safety cylinder; Fig. 1

2 is a sectional elevation along the line 2-2 in Fig. 1 and showing in addition, the safety control rods and lever; Fig. 3 is a fragmenof my safety control rod and lever in a neutral position. 7 g

The reference characters of'the drawings represent like parts throughout the several views, and are identical with those appearing in my -copending applications, mentioned above. The same system of reference is used in order better to co-ordinate the subject matter of the present, with the co-pending applications. V

It will be understood that the safety apparatus herein described represents but a single, embodiment of the present invention, and that substantial changes may be made in the described construction without departing from the scope of this invention, and its underlying principles. The present example is arranged for operative connection with a control shaft, such as 52, by movement of which a full automatic or manual control of other mechanism, such as a drum hoist or drawings, the safety mechanism comprises a cylinder member 125, supported suitably on a base 20. The cylinder provided with a her 129 and head member 126 having an opening 127 therein, which is arranged for connection with the source of fluid pressure through pipe 128. A tubular member 129 is provided at the other end of cylinder 125 and carries a telescoping cap 130 adapted to make a close fit with the outside surface of member 129, but capable of endwise movement with .respect thereto. Cap 130 is provided with lugs 131 on each side, adapted to take the threaded ends of bolts 132. The heads of these bolts are adapted to bear against flange 133 of head 126,and the function ofthe bolts is to maintain the relative position of cap 130 and memher 129. It will be seen'that as bolts 132 are screwed into lugs 131, cap 130 will be moved .to the left along member 129 (Fig. 1') thereby serving as a simple and positive means for adjusting the compression of a resilient member, sum as spring 134adapted to operate Within the chamber 135 formed by memthe inner surface of cap 130. Spring 134 is adapted to operate between the inside end of cap 130 and a piston 136, tending to force the piston to the left in cylinder 125 (Fig. 2). Piston 136 preferably carries a piston rod 137 which projects through opening 138 in cap 130 and is supported at "its free end by means of any suitable bearing member 139. The compression of spring 13 is so adjusted, by means of bolts 132, that when the fluid pressure within cylinder 125 ahead of piston 136, falls below a pre-determined value, the spring will move the piston 136 and rod 137 to its eXtreme-head-end position shown bydotted lines in Fig. 2. The parts of the device are, however, so related that when the fluid pressure in the hydraulic system reaches a predetermined value, the

consequent pressure upon piston 136 through the agency of pipe connection 128 will force the piston to the right against the pressure of spring 134 to the position shown in full lines in Fig. 2. V

Piston rod 137 has a cross head 140 attached thereto in any suitable manner, and adapted to carry pivot pins 141. Rods 142 are preferably attached to cross head 140 by means of the pins 141 and are each provided at their opposite ends with slotted members 143, in

threaded adjusting connection with rods 142.

WVithin each slotted member 143, a roller 144 is adapted to operate, and the rollers'are carried in turn, by a V double-ended lever 145.

Due to the relation between slotted members 143 and rollers 144, a lost-motion relation is provided between the piston rod 137 and shaft 52. Lever 145 may be secured to control shaft 52, either by a key, or through some suitable form of clutch, (not shown) to permit disengagement of the safety mechanism when manual operation of the control shaft is desired. i i r The operation of my described form of safety device will be readily seen by an examination of the drawings. WVhen the mechanism, with which the safety device is associated, is operating normally, and full pressure is maintained in the hydraulic system, piston 136 and rod 137 will occupy substantially the position shown in Fig. 2. Rods 142 will therefore have substantially the position shown with respect to lever 145 and it will be seen, that due to the pivoted mountings of rods 142 and the length of the slots in members 143, lever 145 may be rotated, within limits, either clockwise or counterclockwise with the control shaft 52 during normal operation. This is shown by the dot-ted positions of lever 145 in Fig. 2.

of the left-hand movement of rod 137 will always be to move lever 145 to the vertical position shown. This is evident froman examination of the dotted positions of lever 145 shown in Fig. 3. Any other position of'lever 145, than the one shown in full lines, would evidently require either a pivoted movement "of collar 140 on rod 137, or a shortening of one of the rods 142 and a lengthening of the other rod 142. Since theconstruction is such I as to make this impossible, the effect of a drop in pressure in the hydraulic system will always move lever 145 to a substantially vertical position. Since lever 145 is preferably so connectedto control-shaft 52, that when the lever is in a vertical position, the shaft is so setv that all controls are in neutral, itis evident that a drop in pressure in the hy 'draulic system will innnediately and automavtically set all controls in neutral and stop the hoist'or other equipment.

As willbe obvious from the'preceding description of parts and operation, the presentlydescribed example isintended to be connected to, orto form a part of, a complete hydraulic control-actuating system. Fluid pressure is supplied by apump ofany suitable type, for example the pump shown and describedin my co-pending applicationof Serial No. 146,720, referred to above; By preference, the pressure medium is a suit-' able liquid, such as oil, and is maintain-ed at a relatively constant pressure by a hydraulic accumulator or the like, as described in the last mentioned co-pending application.

WVith an understanding of the presently described device, it is obvious that the. safety apparatus maybe caused to function in a number of ways, responsively to emergency 7 conditions in the equipment with which it is associated; for example, a pressure release valve of any suitable form may be associated with a traveling nut or the like, whose travel is directly correlated with the movement of an elevator, cage, or the winding drum of hoisting equipment.

It will be seen that I have provided a safety device adapted to effect a positive setting of the control shaft of associated equipment, responsive to any failure of hydraulic pressure in the system with which it is connected, in fulfillment of the objects of the invention, as set forth above.

I claim as my invention:

1. A. safety device, adapted for use with a winding mechanism or the like, comprising a control shaft having a position to permit controlling said mechanism, and a neutral position; a piston operatively associated with said shaft, means for supplying a fluid-pressure to said safety device, adapted during normal operation of the winding mechanism to keep the piston at rest, and means opposing said fluid pressure for automatically actuating the piston to move said shaft to its neutral position, whenever the fluid pressure falls below a predetermined value.

2. In a safety apparatus adapted for use with a winding mechanism and the like, a control shaft, a piston operatively associated therewith, means for continuously supplying a fluid pressure to said piston for normally keeping the piston at rest, and means opposing the fluid pressure for rendering said control shaft inoperative, whenever the fluid pressure falls below a predetermined value, and adapted thereby to stop the winding mechanism responsively to sub-normal pressure in sai-dfluid supply means.

3. In a safety device adapted for use with a winding mechanism and the like, means for controlling said mechanism, a normally sta tionary safety piston, means for normally subjecting the piston to opposed differential pressures, including a spring coacting with one face of said piston, means for supplying fluid pressure to the opposite face of said piston to compress said spring, and connecting means between said piston and said controlling means.

l. In a safety apparatus, adapted for use with a winding mechanism or the like, a control shaft having a neutral position distinct fro-1n an active control position, a normally stationary safety piston means subjecting one side of the piston to a constant pressure, fluid supply means on the opposite side of the piston, the piston being normally held in inoperative position by fluid pressure, and connecting means between the piston and the control shaft, whereby the piston will move the shaft to and retain it in neutral position, whenever, the fluid pressure falls below a predetermined value.

5. In a safety apparatus adapted for use with a fluid-pressure controlled mechanism, a control shaft, associated with the mechanism, a lever connected to said shaft, a slotted member operatively engaging said lever, actuating means for said member, coacting therewith for moving said shaft to a neutral position and preventing further movement thereof, responsively to a predetermined low fluid pressure, and fluid pressure means adapted normally to keep the slotted portion of said member in a position to permit a movement of said lever relative thereto.

6. In a safety apparatus adapted for use with a winding mechanism, a control shaft, a piston associated therewith, a piston rod, a spring engaging the piston and tending to move said piston in a direction away from said shaft, a crosshead carried by said pis ton rod, a pair of connectingrods secured to the crosshead, a pair of crank portions carried by thecontrol shaft, slotted connections between said connecting rods'and crank portions, fluid pressure controlled means coact-' ing with the piston for normally maintaining said spring and connecting rods inoperative with respect to said shaft, and means for adjusting said spring. Y

7. In a hydraulic safety device adapted to elfect an automatic emergency control of operating mechanism, a control shaft relating said device and mechanism, a safety piston,

fluid-pressure supply means coacting with the piston and adapted for normally maintaining said piston in inoperative relation to said shaft, and resilient means opposed to the fluid pressure means, and arranged for emergency actuation of said piston and control shaft to an inoperative shaft position.

8. In a hydraulic apparatus'adapted for automatic control of an operating mecha-' nism, a control shaft relating said apparatus and mechanism," means for supplying fluid pressure to said apparatus, and normally b (1 a ara us 1 mo tendmg o malnta n the t n erative relation tOSald. shaft; and pressure means operableindependently of said hy draulic apparatus, and adapted, responsively to subnormal fluid pressure, to actuate the control shaft to render said mechanism inoperative. v 1

9. In a hydraulic safetydevice, a shaft adapted for controlling connection with opl erating mechanism, a piston arranged to be actuated by-fluid pressure, a spring opera.- tively associated with the piston, and tend ing to oppose its actuation by fluid pressure,

a connecting rod between the piston and control shaft, and pivotally associated with the piston, a cylinder for said piston, constituting combined housing and adjusting means for said spring and a lost motion device connecting said rod and control shaft, said device including a crank member secured to the control shaft, and a slotted link engaging the crank member and adjustably secured to the connecting rod.

10. In a safety device, a safety piston,

means for supplying a fluid pressure to said piston, a spring adapted to oppose the effect of said fluid pressure on said piston, and a telescoping member about said spring and adapted to permit, adjustment 7 of the spring pressure.

11. In a hydraulic safety device, a piston arranged to be actuated by fluid pressure, a spring operatively associated with the piston, connecting means between the piston and mechanism to be controlled by said device, and combined enclosing and adjusting means for said spring. 1

12. In a pressure responsive safety device 1 adapted for automatic emergency control of an operating mechanism, a control shaft relating said device. and mechanism, and a lostmotion connection between said pressure responsive device and shaft, adapted normally to permit control movement of the shaft independently of said device, and

adapted to be positioned into positive connec-- tion between said device and shaft, for emergency actuation of said shaft. o

13. A safety device for a fluid pressure control apparatus, including a safety piston, means for supplying fluid pressure to said piston, means for opposing fiuid-movement of the piston, and means normally associating the safety device in lost-motion engagement with the apparatus to be actuatedthere.-

by, and coacting with said opposing means to effect a positive engagement between said device and apparatus responsive to a substantial change in fluid pressure.

14. In a safety device, a cylinder, a piston therein arranged to. be moved, by fluid pressure, a shaft; relating the safety device with apparatus. to be controlled thereby, a piston rod, a connecting rod pivotally associated with the piston rod and in pivoted, operating association withsaid shaft;

15 In a safety device, a cylinder, a piston therein arranged to be moved by fluidpres-- sure, a shaft relating the safety device with apparatus to be controlled thereby,a piston rod, a plurality ofconnecting rods, eachvindependently pivoted to said piston rod, and independently pivotally associated with said control: shaft.

16. In combination with a. control shaft, a safety device including a cylinder, a piston. arranged to move therein; under hydraulic pressure,a piston rod, a plurality of connecting rods, each. independently adjustable in length, pivoted to said; piston rod and independently pivotally associated with the con,

trol. shaft, one of said connecting rods being;

normally associated with the shaftin lost-. motion relation.

FREDERICK n, wHrrEs Ln 

